Infrared attenuated-total-reflection spectroscopy of microcrystalline silicon growth

Abstract In situ Fourier transform infrared attenuated-total-reflection (FT-IR-ATR) spectroscopy has been applied to study the growth of μc-Si:H from an rf glow discharge decomposition of H2-diluted SiH4 and from a layer-by-layer (LbL) process in which 3 nm-thick Si:H deposition and H2-plasma annealing are alternately repeated. The results indicate that the FT-IR-ATR technique enables us to measure the nucleation and the grain growth with a submonolayer sensitivity. During the μc-Si:H growth, the time evolution of the absorption intensity of the stretching modes due to interior silicon hydrides is suppressed and distinct absorption peaks due to surface hydrides emerge, which are not observable in the case for a-Si:H film growth. Temporal changes in the ATR spectrum during the LbL process at 250°C have shown that the hydrogen desorption from a near surface region, especially the grain boundary and amorphous phase, caused by H2-plasma exposure affects the crystalline nucleation and the grain growth.